libpthread/nptl/sysdeps/i386/tls.h

   1 /* Definition for thread-local data handling.  nptl/i386 version.
   2    Copyright (C) 2002-2007, 2009 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _TLS_H
  21 #define _TLS_H  1
  22
  23 #ifndef __ASSEMBLER__
  24 # include <stdbool.h>
  25 # include <stddef.h>
  26 # include <stdint.h>
  27 # include <stdlib.h>
  28 # include <list.h>
  29 # include <sysdep.h>
  30 # include <bits/kernel-features.h>
  31
  32
  33 /* Type for the dtv.  */
  34 typedef union dtv
  35 {
  36   size_t counter;
  37   struct
  38   {
  39     void *val;
  40     bool is_static;
  41   } pointer;
  42 } dtv_t;
  43
  44
  45 typedef struct
  46 {
  47   void *tcb;            /* Pointer to the TCB.  Not necessarily the
  48                            thread descriptor used by libpthread.  */
  49   dtv_t *dtv;
  50   void *self;           /* Pointer to the thread descriptor.  */
  51   int multiple_threads;
  52   uintptr_t sysinfo;
  53   uintptr_t stack_guard;
  54   uintptr_t pointer_guard;
  55   int gscope_flag;
  56 #ifndef __ASSUME_PRIVATE_FUTEX
  57   int private_futex;
  58 #else
  59   int __unused1;
  60 #endif
  61   /* Reservation of some values for the TM ABI.  */
  62   void *__private_tm[5];
  63 } tcbhead_t;
  64
  65 # define TLS_MULTIPLE_THREADS_IN_TCB 1
  66
  67 #else /* __ASSEMBLER__ */
  68 # include <tcb-offsets.h>
  69 #endif
  70
  71
  72 /* We require TLS support in the tools.  */
  73 #define HAVE_TLS_SUPPORT
  74 #define HAVE___THREAD 1
  75 #define HAVE_TLS_MODEL_ATTRIBUTE 1
  76
  77 /* Signal that TLS support is available.  */
  78 #define USE_TLS        1
  79
  80
  81 /* Alignment requirement for the stack.  For IA-32 this is governed by
  82    the SSE memory functions.  */
  83 #define STACK_ALIGN     16
  84
  85 #ifndef __ASSEMBLER__
  86 /* Get system call information.  */
  87 # include <sysdep.h>
  88
  89 /* The old way: using LDT.  */
  90
  91 /* Structure passed to `modify_ldt', 'set_thread_area', and 'clone' calls.  */
  92 struct user_desc
  93 {
  94   unsigned int entry_number;
  95   unsigned long int base_addr;
  96   unsigned int limit;
  97   unsigned int seg_32bit:1;
  98   unsigned int contents:2;
  99   unsigned int read_exec_only:1;
 100   unsigned int limit_in_pages:1;
 101   unsigned int seg_not_present:1;
 102   unsigned int useable:1;
 103   unsigned int empty:25;
 104 };
 105
 106 /* Initializing bit fields is slow.  We speed it up by using a union.  */
 107 union user_desc_init
 108 {
 109   struct user_desc desc;
 110   unsigned int vals[4];
 111 };
 112
 113
 114 /* Get the thread descriptor definition.  */
 115 # include <descr.h>
 116
 117 /* This is the size of the initial TCB.  Can't be just sizeof (tcbhead_t),
 118    because NPTL getpid, __libc_alloca_cutoff etc. need (almost) the whole
 119    struct pthread even when not linked with -lpthread.  */
 120 # define TLS_INIT_TCB_SIZE sizeof (struct pthread)
 121
 122 /* Alignment requirements for the initial TCB.  */
 123 # define TLS_INIT_TCB_ALIGN __alignof__ (struct pthread)
 124
 125 /* This is the size of the TCB.  */
 126 # define TLS_TCB_SIZE sizeof (struct pthread)
 127
 128 /* Alignment requirements for the TCB.  */
 129 # define TLS_TCB_ALIGN __alignof__ (struct pthread)
 130
 131 /* The TCB can have any size and the memory following the address the
 132    thread pointer points to is unspecified.  Allocate the TCB there.  */
 133 # define TLS_TCB_AT_TP  1
 134
 135
 136 /* Install the dtv pointer.  The pointer passed is to the element with
 137    index -1 which contain the length.  */
 138 # define INSTALL_DTV(descr, dtvp) \
 139   ((tcbhead_t *) (descr))->dtv = (dtvp) + 1
 140
 141 /* Install new dtv for current thread.  */
 142 # define INSTALL_NEW_DTV(dtvp) \
 143   ({ struct pthread *__pd;                                                    \
 144      THREAD_SETMEM (__pd, header.dtv, (dtvp)); })
 145
 146 /* Return dtv of given thread descriptor.  */
 147 # define GET_DTV(descr) \
 148   (((tcbhead_t *) (descr))->dtv)
 149
 150 #define THREAD_SELF_SYSINFO     THREAD_GETMEM (THREAD_SELF, header.sysinfo)
 151 #define THREAD_SYSINFO(pd)      ((pd)->header.sysinfo)
 152
 153 /* Macros to load from and store into segment registers.  */
 154 # ifndef TLS_GET_GS
 155 #  define TLS_GET_GS() \
 156   ({ int __seg; __asm__ ("movw %%gs, %w0" : "=q" (__seg)); __seg & 0xffff; })
 157 # endif
 158 # ifndef TLS_SET_GS
 159 #  define TLS_SET_GS(val) \
 160   __asm__ ("movw %w0, %%gs" :: "q" (val))
 161 # endif
 162
 163
 164 # ifndef __NR_set_thread_area
 165 #  define __NR_set_thread_area 243
 166 # endif
 167 # ifndef TLS_FLAG_WRITABLE
 168 #  define TLS_FLAG_WRITABLE             0x00000001
 169 # endif
 170
 171 // XXX Enable for the real world.
 172 #if 0
 173 # ifndef __ASSUME_SET_THREAD_AREA
 174 #  error "we need set_thread_area"
 175 # endif
 176 #endif
 177
 178 # ifdef __PIC__
 179 #  define TLS_EBX_ARG "r"
 180 #  define TLS_LOAD_EBX "xchgl %3, %%ebx\n\t"
 181 # else
 182 #  define TLS_EBX_ARG "b"
 183 #  define TLS_LOAD_EBX
 184 # endif
 185
 186 #if defined NEED_DL_SYSINFO
 187 # define INIT_SYSINFO \
 188   _head->sysinfo = GLRO(dl_sysinfo)
 189 #else
 190 # define INIT_SYSINFO
 191 #endif
 192
 193 #ifndef LOCK_PREFIX
 194 # ifdef UP
 195 #  define LOCK_PREFIX  /* nothing */
 196 # else
 197 #  define LOCK_PREFIX "lock;"
 198 # endif
 199 #endif
 200
 201 /* Code to initially initialize the thread pointer.  This might need
 202    special attention since 'errno' is not yet available and if the
 203    operation can cause a failure 'errno' must not be touched.  */
 204 # define TLS_INIT_TP(thrdescr, secondcall) \
 205   ({ void *_thrdescr = (thrdescr);                                            \
 206      tcbhead_t *_head = _thrdescr;                                            \
 207      union user_desc_init _segdescr;                                          \
 208      int _result;                                                             \
 209                                                                               \
 210      _head->tcb = _thrdescr;                                                  \
 211      /* For now the thread descriptor is at the same address.  */             \
 212      _head->self = _thrdescr;                                                 \
 213      /* New syscall handling support.  */                                     \
 214      INIT_SYSINFO;                                                            \
 215                                                                               \
 216      /* The 'entry_number' field.  Let the kernel pick a value.  */           \
 217      if (secondcall)                                                          \
 218        _segdescr.vals[0] = TLS_GET_GS () >> 3;                                \
 219      else                                                                     \
 220        _segdescr.vals[0] = -1;                                                \
 221      /* The 'base_addr' field.  Pointer to the TCB.  */                       \
 222      _segdescr.vals[1] = (unsigned long int) _thrdescr;                       \
 223      /* The 'limit' field.  We use 4GB which is 0xfffff pages.  */            \
 224      _segdescr.vals[2] = 0xfffff;                                             \
 225      /* Collapsed value of the bitfield:                                      \
 226           .seg_32bit = 1                                                      \
 227           .contents = 0                                                       \
 228           .read_exec_only = 0                                                 \
 229           .limit_in_pages = 1                                                 \
 230           .seg_not_present = 0                                                \
 231           .useable = 1 */                                                     \
 232      _segdescr.vals[3] = 0x51;                                                \
 233                                                                               \
 234      /* Install the TLS.  */                                                  \
 235      __asm__ volatile (TLS_LOAD_EBX                                               \
 236                    "int $0x80\n\t"                                            \
 237                    TLS_LOAD_EBX                                               \
 238                    : "=a" (_result), "=m" (_segdescr.desc.entry_number)       \
 239                    : "0" (__NR_set_thread_area),                              \
 240                      TLS_EBX_ARG (&_segdescr.desc), "m" (_segdescr.desc));    \
 241                                                                               \
 242      if (_result == 0)                                                        \
 243        /* We know the index in the GDT, now load the segment register.        \
 244           The use of the GDT is described by the value 3 in the lower         \
 245           three bits of the segment descriptor value.                         \
 246                                                                               \
 247           Note that we have to do this even if the numeric value of           \
 248           the descriptor does not change.  Loading the segment register       \
 249           causes the segment information from the GDT to be loaded            \
 250           which is necessary since we have changed it.   */                   \
 251        TLS_SET_GS (_segdescr.desc.entry_number * 8 + 3);                      \
 252                                                                               \
 253      _result == 0 ? NULL                                                      \
 254      : "set_thread_area failed when setting up thread-local storage\n"; })
 255
 256
 257 /* Return the address of the dtv for the current thread.  */
 258 # define THREAD_DTV() \
 259   ({ struct pthread *__pd;                                                    \
 260      THREAD_GETMEM (__pd, header.dtv); })
 261
 262
 263 /* Return the thread descriptor for the current thread.
 264
 265    The contained asm must *not* be marked volatile since otherwise
 266    assignments like
 267         pthread_descr self = thread_self();
 268    do not get optimized away.  */
 269 # define THREAD_SELF \
 270   ({ struct pthread *__self;                                                  \
 271      __asm__ ("movl %%gs:%c1,%0" : "=r" (__self)                                    \
 272           : "i" (offsetof (struct pthread, header.self)));                    \
 273      __self;})
 274
 275 /* Magic for libthread_db to know how to do THREAD_SELF.  */
 276 # define DB_THREAD_SELF \
 277   REGISTER_THREAD_AREA (32, offsetof (struct user_regs_struct, xgs), 3) \
 278   REGISTER_THREAD_AREA (64, 26 * 8, 3) /* x86-64's user_regs_struct->gs */
 279
 280
 281 /* Read member of the thread descriptor directly.  */
 282 # define THREAD_GETMEM(descr, member) \
 283   ({ __typeof (descr->member) __value;                                        \
 284      if (sizeof (__value) == 1)                                               \
 285        __asm__ volatile ("movb %%gs:%P2,%b0"                                \
 286                      : "=q" (__value)                                         \
 287                      : "0" (0), "i" (offsetof (struct pthread, member)));     \
 288      else if (sizeof (__value) == 4)                                          \
 289        __asm__ volatile ("movl %%gs:%P1,%0"                                         \
 290                      : "=r" (__value)                                         \
 291                      : "i" (offsetof (struct pthread, member)));              \
 292      else                                                                     \
 293        {                                                                      \
 294          if (sizeof (__value) != 8)                                           \
 295            /* There should not be any value with a size other than 1,         \
 296               4 or 8.  */                                                     \
 297            abort ();                                                          \
 298                                                                               \
 299          __asm__ volatile ("movl %%gs:%P1,%%eax\n\t"                          \
 300                        "movl %%gs:%P2,%%edx"                                  \
 301                        : "=A" (__value)                                       \
 302                        : "i" (offsetof (struct pthread, member)),             \
 303                          "i" (offsetof (struct pthread, member) + 4));        \
 304        }                                                                      \
 305      __value; })
 306
 307
 308 /* Same as THREAD_GETMEM, but the member offset can be non-constant.  */
 309 # define THREAD_GETMEM_NC(descr, member, idx) \
 310   ({ __typeof (descr->member[0]) __value;                                     \
 311      if (sizeof (__value) == 1)                                               \
 312        __asm__ volatile ("movb %%gs:%P2(%3),%b0"                                      \
 313                      : "=q" (__value)                                         \
 314                      : "0" (0), "i" (offsetof (struct pthread, member[0])),   \
 315                      "r" (idx));                                              \
 316      else if (sizeof (__value) == 4)                                          \
 317        __asm__ volatile ("movl %%gs:%P1(,%2,4),%0"                                    \
 318                      : "=r" (__value)                                         \
 319                      : "i" (offsetof (struct pthread, member[0])),            \
 320                        "r" (idx));                                            \
 321      else                                                                     \
 322        {                                                                      \
 323          if (sizeof (__value) != 8)                                           \
 324            /* There should not be any value with a size other than 1,         \
 325               4 or 8.  */                                                     \
 326            abort ();                                                          \
 327                                                                               \
 328          __asm__ volatile  ("movl %%gs:%P1(,%2,8),%%eax\n\t"                  \
 329                         "movl %%gs:4+%P1(,%2,8),%%edx"                        \
 330                         : "=&A" (__value)                                     \
 331                         : "i" (offsetof (struct pthread, member[0])),         \
 332                           "r" (idx));                                         \
 333        }                                                                      \
 334      __value; })
 335
 336
 337 /* Same as THREAD_SETMEM, but the member offset can be non-constant.  */
 338 # define THREAD_SETMEM(descr, member, value) \
 339   ({ if (sizeof (descr->member) == 1)                                         \
 340        __asm__ volatile ("movb %b0,%%gs:%P1" :                                \
 341                      : "iq" (value),                                          \
 342                        "i" (offsetof (struct pthread, member)));              \
 343      else if (sizeof (descr->member) == 4)                                    \
 344        __asm__ volatile ("movl %0,%%gs:%P1" :                                 \
 345                      : "ir" (value),                                          \
 346                        "i" (offsetof (struct pthread, member)));              \
 347      else                                                                     \
 348        {                                                                      \
 349          if (sizeof (descr->member) != 8)                                     \
 350            /* There should not be any value with a size other than 1,         \
 351               4 or 8.  */                                                     \
 352            abort ();                                                          \
 353                                                                               \
 354          __asm__ volatile ("movl %%eax,%%gs:%P1\n\t"                          \
 355                        "movl %%edx,%%gs:%P2" :                                \
 356                        : "A" (value),                                         \
 357                          "i" (offsetof (struct pthread, member)),             \
 358                          "i" (offsetof (struct pthread, member) + 4));        \
 359        }})
 360
 361
 362 /* Set member of the thread descriptor directly.  */
 363 # define THREAD_SETMEM_NC(descr, member, idx, value) \
 364   ({ if (sizeof (descr->member[0]) == 1)                                      \
 365        __asm__ volatile ("movb %b0,%%gs:%P1(%2)" :                                    \
 366                      : "iq" (value),                                          \
 367                        "i" (offsetof (struct pthread, member)),               \
 368                        "r" (idx));                                            \
 369      else if (sizeof (descr->member[0]) == 4)                                 \
 370        __asm__ volatile ("movl %0,%%gs:%P1(,%2,4)" :                          \
 371                      : "ir" (value),                                          \
 372                        "i" (offsetof (struct pthread, member)),               \
 373                        "r" (idx));                                            \
 374      else                                                                     \
 375        {                                                                      \
 376          if (sizeof (descr->member[0]) != 8)                                  \
 377            /* There should not be any value with a size other than 1,         \
 378               4 or 8.  */                                                     \
 379            abort ();                                                          \
 380                                                                               \
 381          __asm__ volatile ("movl %%eax,%%gs:%P1(,%2,8)\n\t"                           \
 382                        "movl %%edx,%%gs:4+%P1(,%2,8)" :                       \
 383                        : "A" (value),                                         \
 384                          "i" (offsetof (struct pthread, member)),             \
 385                          "r" (idx));                                          \
 386        }})
 387
 388
 389 /* Atomic compare and exchange on TLS, returning old value.  */
 390 #define THREAD_ATOMIC_CMPXCHG_VAL(descr, member, newval, oldval) \
 391   ({ __typeof (descr->member) __ret;                                          \
 392      __typeof (oldval) __old = (oldval);                                      \
 393      if (sizeof (descr->member) == 4)                                         \
 394        __asm__ volatile (LOCK_PREFIX "cmpxchgl %2, %%gs:%P3"                  \
 395                      : "=a" (__ret)                                           \
 396                      : "0" (__old), "r" (newval),                             \
 397                        "i" (offsetof (struct pthread, member)));              \
 398      else                                                                     \
 399        /* Not necessary for other sizes in the moment.  */                    \
 400        abort ();                                                              \
 401      __ret; })
 402
 403
 404 /* Atomic logical and.  */
 405 #define THREAD_ATOMIC_AND(descr, member, val) \
 406   (void) ({ if (sizeof ((descr)->member) == 4)                                \
 407               __asm__ volatile (LOCK_PREFIX "andl %1, %%gs:%P0"               \
 408                             :: "i" (offsetof (struct pthread, member)),       \
 409                                "ir" (val));                                   \
 410             else                                                              \
 411               /* Not necessary for other sizes in the moment.  */             \
 412               abort (); })
 413
 414
 415 /* Atomic set bit.  */
 416 #define THREAD_ATOMIC_BIT_SET(descr, member, bit) \
 417   (void) ({ if (sizeof ((descr)->member) == 4)                                \
 418               __asm__ volatile (LOCK_PREFIX "orl %1, %%gs:%P0"                \
 419                             :: "i" (offsetof (struct pthread, member)),       \
 420                                "ir" (1 << (bit)));                            \
 421             else                                                              \
 422               /* Not necessary for other sizes in the moment.  */             \
 423               abort (); })
 424
 425
 426 /* Call the user-provided thread function.  */
 427 #define CALL_THREAD_FCT(descr) \
 428   ({ void *__res;                                                             \
 429      int __ignore1, __ignore2;                                                \
 430      __asm__ volatile ("pushl %%eax\n\t"                                              \
 431                    "pushl %%eax\n\t"                                          \
 432                    "pushl %%eax\n\t"                                          \
 433                    "pushl %%gs:%P4\n\t"                                       \
 434                    "call *%%gs:%P3\n\t"                                       \
 435                    "addl $16, %%esp"                                          \
 436                    : "=a" (__res), "=c" (__ignore1), "=d" (__ignore2)         \
 437                    : "i" (offsetof (struct pthread, start_routine)),          \
 438                      "i" (offsetof (struct pthread, arg)));                   \
 439      __res; })
 440
 441
 442 /* Set the stack guard field in TCB head.  */
 443 #define THREAD_SET_STACK_GUARD(value) \
 444   THREAD_SETMEM (THREAD_SELF, header.stack_guard, value)
 445 #define THREAD_COPY_STACK_GUARD(descr) \
 446   ((descr)->header.stack_guard                                                \
 447    = THREAD_GETMEM (THREAD_SELF, header.stack_guard))
 448
 449
 450 /* Set the pointer guard field in the TCB head.  */
 451 #define THREAD_SET_POINTER_GUARD(value) \
 452   THREAD_SETMEM (THREAD_SELF, header.pointer_guard, value)
 453 #define THREAD_COPY_POINTER_GUARD(descr) \
 454   ((descr)->header.pointer_guard                                              \
 455    = THREAD_GETMEM (THREAD_SELF, header.pointer_guard))
 456
 457
 458 /* Get and set the global scope generation counter in the TCB head.  */
 459 #define THREAD_GSCOPE_FLAG_UNUSED 0
 460 #define THREAD_GSCOPE_FLAG_USED   1
 461 #define THREAD_GSCOPE_FLAG_WAIT   2
 462 #define THREAD_GSCOPE_RESET_FLAG() \
 463   do                                                                          \
 464     { int __res;                                                              \
 465       __asm__ volatile ("xchgl %0, %%gs:%P1"                                  \
 466                     : "=r" (__res)                                            \
 467                     : "i" (offsetof (struct pthread, header.gscope_flag)),    \
 468                       "0" (THREAD_GSCOPE_FLAG_UNUSED));                       \
 469       if (__res == THREAD_GSCOPE_FLAG_WAIT)                                   \
 470         lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE);    \
 471     }                                                                         \
 472   while (0)
 473 #define THREAD_GSCOPE_SET_FLAG() \
 474   THREAD_SETMEM (THREAD_SELF, header.gscope_flag, THREAD_GSCOPE_FLAG_USED)
 475 #define THREAD_GSCOPE_WAIT() \
 476   GL(dl_wait_lookup_done) ()
 477
 478 #endif /* __ASSEMBLER__ */
 479
 480 #endif  /* tls.h */